The Lord Mayor of London, Roger Gifford, rehearses on Monday for the funeral of former British prime minister Margaret Thatcher, at St. Paul's Cathedral in the City of London. Photo: Reuters

The ceremonial funeral with full military honours afforded former British prime minister Margaret Thatcher is just a few technical steps away from a full-blown state funeral.

The Iron Lady will be given a send-off full of pomp and ceremony involving 700 members of the armed forces, gunfire salutes and 2,000 guests at St Paul’s Cathedral in London on Wednesday.

The differences between a ceremonial funeral and a state funeral will not be recognised by the vast majority of the viewing public.

And like many elements of traditional British protocol, it relies as much on memory, precedent and the wishes of those involved as on written rules.

State funerals in Britain are afforded to monarchs and, down the centuries, very few exceptionally distinguished individuals.

The last one was that of World War II prime minister Winston Churchill in 1965, which, like Thatcher’s, was held at St Paul’s.

It was perhaps a wise move on Thatcher’s part to decline a state funeral given that such as event must be approved by a vote in parliament.

Lawmakers remain bitterly divided over the legacy of the Conservative politician, who introduced radical free market reforms and transformed Britain during her 11 years in power.

Other recipients of a state funeral include scientist Isaac Newton (1727), Battle of Trafalgar hero Horatio Nelson (1806), Battle of Waterloo victor the Duke of Wellington (1852) and four-times prime minister William Gladstone (1898).

The last ceremonial funerals were for queen Elizabeth, the queen mother, in 2002 and for Diana, princess of Wales in 1997 – both grand occasions with very similar trappings.

In either type of funeral, there is typically a military procession carrying the coffin through London to Westminster Hall (the oldest part of the Houses of Parliament), a period of lying in state, and a service at Westminster Abbey or St Paul’s Cathedral.

A House of Commons library note explaining the distinction between a state and ceremonial funeral says the former “is commonly held to differ from a ceremonial funeral in two respects: a parliamentary motion authorises it, and the gun carriage bearing the coffin to the lying in state has, since the funeral of queen Victoria (1901), been drawn by Royal Navy sailors rather than by horses.”

Lord Tim Bell, Thatcher’s friend and spokesman, said the 20th century’s longest-serving premier decided herself that she did not want a funeral on the scale of Churchill’s.

“She specifically did not want a state funeral and nor did her family,” he said.

“She particularly did not wish to lie in state as she thought that was not appropriate,” he added.

“And she didn’t want a fly-past as she thought that was a waste of money -- somewhat in character, you might think.”

Announcing the type of funeral, Downing Street said it was “in line with the wishes of her family and with the queen’s consent”.

“Lady Thatcher’s wish was for the armed forces to be able to take part,” it added, clearly showing that the baroness had been involved with its planning.

A estimate for the funeral’s total cost will be given afterwards.

The hymns, music and readings in the funeral service were selected meticulously by Thatcher, a churchgoing Methodist whose political beliefs were grounded in her strong faith.